Impact of Tumor Size on Patients With Hepatocellular Carcinoma Treated With Stereotactic Ablative Radiotherapy

Stereotactic ablative radiotherapy (SABR) can deliver tumoricidal doses to hepatocellular carcinoma (HCC). To date, there is a paucity of research reporting the impact of maximal tumor diameter (MTD) on patients with HCC treated with SABR.

The medical records of patients with HCC with Barcelona Clinic Liver Cancer (BCLC) stage A to C diseases treated with linear accelerator-based SABR between 2015 and 2021 were reviewed. Overall survival (OS), in-field progression-free survival (IFPFS), out-field progression-free survival (OFPFS), and distant metastasis-free survival (DMFS) were calculated using Kaplan-Meier analysis. The Cox regression model was performed to examine the effects of variables.

This retrospective study included 62 patients. The median MTD and measured tumor volume were 5.3 cm (range=1.7-10 cm) and 41 ml (range=3.2-454 ml), respectively. Thirty-one patients (50%) had vascular invasion. Patients received a median prescribed dose of 48 Gy (30-54 Gy) in five to six fractions. Over a median follow-up of 19 months (range=4-66 months), six, 36, and 25 patients experienced in-field failure, out-field hepatic recurrence, and extrahepatic metastases, respectively. The estimated 2-year OS and IFPFS rates were 45.9% and 90.6%, respectively. In the univariate analysis, MTD over 5.3 cm was associated with inferior OS. In the multivariate analysis, MTD or other clinical parameters failed to influence any clinical endpoints. A total of nine patients (14.5%) developed radiation-induced liver disease.

A MTD up to 10 cm did not significantly impact in-field progression following SABR. Although the prescribed dose of 48 Gy in five to six fractions can achieve superior in-field control, most treatment failures were due to out-field relapse.